This invention relates generally to power drive wheelchairs of the type having on-board drive means for rotatably driving the wheelchair wheels. More particularly, this invention relates to an improved power drive wheelchair constructed from modular components or subassemblies to permit wheelchair disassembly into a small number of compact modules adapted for easy transport and/or storage.
Power drive wheelchairs in general are known in the art to provide motorized mobility to persons confined to a wheelchair. Such power drive wheelchairs conventionally comprise a relatively sturdy wheelchair frame supported on wheels for rolling movement, in combination with one or more batteries for supplying electrical power to an associated drive motor or motors coupled to the wheelchair wheels. An electronic controller unit is also carried by the wheelchair to regulate power driven operation of the drive motor or motors, typically in accordance with positioning of a joystick type control mechanism or the like located in close proximity to a wheelchair seat. In many modern power drive wheelchairs, the controller unit utilizes pulse width modulation techniques to regulate a pair of drive motors in a manner permitting simple joystick selection of wheelchair drive direction and speed. For one example of a power drive wheelchair of this general type, see U.S. Pat. No. 4,549,624.
Although power drive wheelchairs of the general type described above are capable of providing great improvements in overall mobility and independence to wheelchair patients, the necessary drive components have resulted in relatively heavy and costly wheelchair constructions. More specifically, the requisite power storage batteries and related drive motors and control components result in a relatively heavy wheelchair construction having a gross weight commonly in excess of one hundred pounds. This relatively heavy chair weight has required a correspondingly heavy duty wheelchair frame designed to support the drive components and the wheelchair patient without significant mechanical instability or risk of mechanical failure. As a result, power drive wheelchairs have used relatively heavy rigid frames having low centers of gravity to insure reliable and safe operation. However, such configurations are not designed for easy handling or for disassembly or folding into a compact shape for easy transport in a standard passenger automobile or the like. Instead, vehicle transport of a power drive wheelchair has normally been limited to the use of vans or trucks or other specialized vehicles having, for example, power lift mechanisms for loading and unloading the heavy wheelchair from the vehicle. Moreover, the rigid frame requirements for power drive wheelchairs have generally precluded significant size adjustment capabilities as may be desired, for example, in a wheelchair used by a growing child or adolescent. Instead, to meet changing size requirements, it has been necessary to acquire a different wheelchair.
There exists, therefore, a significant need for an improved power drive wheelchair designed for rapid assembly and disassembly of modular components to accommodate facilitated transport in a standard passenger automobile or the like. Moreover, there exists a need for a power drive wheelchair adapted for a range of size adjustments to meet changing size requirements of a wheelchair patient. The present invention fulfills these needs and provides further related advantages.